前瞻性心电门控技术80kV-CT冠脉造影的临床应用研究

Clinical Research of 80 kV-CT Coronary Angiography for Prospectively Gated Axial Technique

目的：评价80 k V-CT冠脉造影图像质量与辐射剂量,明确其临床应用价值。方法：选取拟行CT冠状动脉造影的患者61例,随机分为两组。A组管电压设置为80 k V,管电流300--450 m A;B组管电压设置为120 k V,管电流200--350 m A。比较A和B两组的主观图像质量、客观图像质量（CT值、噪声值、SNR、CNR）及辐射剂量。P〈0.05认为差异有统计学意义。结果：A组平均得分3.36±0.68,B组平均得分4.58±0.67,A组与B组（t=-25.859,P=0.000）差异有统计学意义。A组可评估率为97.32%,B组可评估率为99.02%,A组与B组（χ2=3.276,P=0.070）差异无统计学意义。主动脉根部CT值,A组为（573.11±150.42）HU,B组为（428.41±95.32）HU,A组与B组（t=4.434,P=0.000）差异具有统计学意义;主动脉根部噪声值,A组为（43.32±12.25）HU,B组为（28.79±7.61）HU,A组与B组（t=5.488,P=0.000）差异具有统计学意义;主动脉根部SNR,A组为13.99±4.80,B组为14.78±3.50,A组与B组（t=-0.725,P=0.471）差异无统计学意义;主动脉根部CNR,A组为16.25±5.18,B组为18.82±4.65,A组与B组（t=-2.031,P=0.047）差异具有统计学意义;A组ED为（0.95±0.09）m Sv,B组ED为（2.07±0.21）m Sv,A组与B组（t=-28.052,P=0.000）差异有统计学意义。结论：通过适当提高管电流的80 k V-CTCA可以大幅减低辐射剂量,而图像质量可满足诊断。

Objective： To evaluate image quality and radiation dose for coronary artery computed tomographic angiography（CTA） obtained with 80 k V. Methods： 61 patients enrolled in this study were randomly divided into two groups. The group A was 32 patients with tube voltage 80 k V and tube current（200-350）m A. The group B was 29 patients with tube voltage 120 k V and tube current（300-450）m A. Two groups were evaluated for the image quality score, mean attenuation, noise, signal-to-noise ratio（SNR） and contrast-to-noise（CNR） in aortic root and radiation dose. The image quality and radiation dose was compared by Chi-square test and unpaired t-test. A P value below 0.05 was considered to be statistically significant. Results： The aortic root showed significantly higher mean image quality score, mean attenuation, noise and CNR in group A than in group B（P = 0.000, P = 0.000, P = 0.000, P = 0.047, respectively）. The SNR was not statistically significant for group A versus group B（P = 0.471）. The percentage of assessable coronary artery segments was no statistically significant for group B versus group A（χ2= 3.276, P = 0.070）. The mean effective dose was statistically significant for the group A was 0.95 m Sv versus 2.07 m Sv for the group B（t =-28.052, P = 0.000）. Conclusion： 80 k V-CTCA with higher tube current could offer assessable image quality and substantially reduced effective radiation dose.